Listeria Monocytogenes Bacteria

Like Salmonella, Listeria is found everywhere – in soil, vegetation, and water. Found frequently in the intestinal tracts of many animals, Listeria travels in the feces where it can end up in sewage and/or contaminate the water supply. Common carriers of Listeria are vegetables grown in soil fertilized with manure, and raw milk or the cheeses made from it. Seafood has also been identified as a source of Listeria contamination. Listeria outbreaks have been attributed to contaminated cabbage, pasteurized milk, luncheon meats, and Mexican-style soft cheese that had been processed with some raw milk.

One of the major problems with Listeria monocytogenes is its versatility. It is a facultative bacteria, which means it is capable of growing with or without oxygen; it can survive a wide range of pH (from 4.8 to 9.0); and it grows in a wide temperature range (39° to 113°F/ 4° to 45°C), allowing it to thrive at refrigerator temperatures. Even frozen dairy desserts have been implicated in Listeria monocytogenes contamination.

Fatality rates from Listeria monocytogenes infection are as high as 20 to 35 percent. Lysteria infection may also cause pneumonia, septicemia, urethritis, meningitis, and spontaneous abortion.